docs: def to_sdp(self):
          """
          Return a string representation suitable for SDP.
          """
          sdp = '%s %d %s %d %s %d typ %s' % (
              self.foundation,
              self.component,
              self.transport,
              self.priority,
              self.host,
              self.port,
              self.type)
          if self.related_address is not None:
              sdp += ' raddr %s' % self.related_address
          if self.related_port is not None:
              sdp += ' rport %s' % self.related_port
          if self.tcptype is not None:
              sdp += ' tcptype %s' % self.tcptype
          if self.generation is not None:
              sdp += ' generation %d' % self.generation
          return sdp